1) The purpose of this project is to refine a pneumatically powered impact noise generator whose peak level, rise time, and decay can be experimentally manipulated. Mechanical, acoustic and reliability parameters are being measured currently in preparation for (animal) exposure experiments. 2) A closed system electroacoustic transducer having the ability to deliver high level, wide band minimum distortion sounds to the eardrum of guinea pigs has long been needed. Purpose to develop such a device. 3) Purpose is to develop a simple instrument with which significant speech discrimination test parameters can be manipulated. These parameters include peak level, long-term equivalent level, defined pink noise and speech spectrum noise for masking purposes and a means for modulating both. 4) Design of the necessary electro optics for resolution of 10 to the minus 9 watts (DC) of 8200 Angstrom illumination returned from the vibrating lasilar membrane. Design requirements were 25 kHz BW and noise at or below inescapable photo current generated shot noise levels, and approximately 1 Angstrom/Hz resolution.